While performing "Unapologetic Bitch," Madonna, 57, led Chastain up the middle of the stage before the actress showed off her killer dance moves. Madge then crawled on the dance floor in front of Chastain, 38, who unleashed several taps on the mega-stars bum.

"I gave Madonna a spanking & I've [got] a video to prove it," The Martian star wrote on Facebook, later sharing a picture of herself hand-in-hand with the "Bitch I'm Madonna" singer.

"The moment right before@madonna handed me a banana. The fkn Queen," she captioned the pic.